2.5D spectral finite-difference method for geophysical applications

The 2.5D forward method has been widely used in geophysical applications such as single-well, cross-well and controlled source electromagnetic measurements [1]. In this work, we proposed a two-dimensional (2-D) finite-difference frequency domain method for solving geophysical prospecting problems. The method is based on spectral domain and all the field quantities are expanded using Fourier transformation. Starting from the two-curl Maxwell equations, the longitudinal field components are eliminated and four transverse field components are used to represent the unknown fields [2]. The discretization is based on staggered Yee grid. The perfect electric conductor (PEC) boundary condition is employed to truncate the interested domain provided that the source is sufficiently far away to the boundary. The resulted system matrix is being solved using different methods and validated through eigenvalue problems. When finite source excitation is used, our numerical results show that good agreement is achieved compared with analytic solution.